Malposition detection system

ABSTRACT

Disclosed herein is a system, apparatus and method directed to detecting malposition of a medical device within a vessel of a patient, such as an Azygos vein. The medical device can include a multi-core optical fiber including a plurality of core fibers, where each of the plurality of core fibers includes a plurality of sensors is configured to reflect a light signal based on received incident light, and change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber. The system can include a console having non-transitory computer-readable medium storing logic that, when executed, causes operations of providing a broadband incident light signal to the multi-core optical fiber, receiving reflected light signals, processing the reflected light signals, and determining whether the medical device has entered the Azygos vein of the patient based on the reflected light signals.

PRIORITY

This application claims the benefit of priority to U.S. Provisional Application No. 63/044,911, filed Jun. 26, 2020, which is incorporated by reference in its entirety into this application.

BACKGROUND

In the past, certain intravascular guidance of medical devices, such as guidewires and catheters for example, have used fluoroscopic methods for tracking tips of the medical devices and determining whether distal tips are appropriately localized in their target anatomical structures. However, such fluoroscopic methods expose patients and their attending clinicians to harmful X-ray radiation. Moreover, in some cases, the patients are exposed to potentially harmful contrast media needed for the fluoroscopic methods.

More recently, electromagnetic tracking systems have been used involving stylets. Generally, electromagnetic tracking systems feature three components: a field generator, a sensor unit and control unit. The field generator uses several coils to generate a position-varying magnetic field, which is used to establish a coordinate space. Attached to the stylet, such as near a distal end (tip) of the stylet for example, the sensor unit includes small coils in which current is induced via the magnetic field. Based on the electrical properties of each coil, the position and orientation of the medical device may be determined within the coordinate space. The control unit controls the field generator and captures data from the sensor unit.

Although electromagnetic tracking systems avoid line-of-sight reliance in tracking the tip of a stylet while obviating radiation exposure and potentially harmful contrast media associated with fluoroscopic methods, electromagnetic tracking systems are prone to interference. More specifically, since electromagnetic tracking systems depend on the measurement of magnetic fields produced by the field generator, these systems are subject to electromagnetic field interference, which may be caused by the presence of many different types of consumer electronics such as cellular telephones. Additionally, electromagnetic tracking systems are subject to signal drop out, depend on an external sensor, and are defined to a limited depth range.

Disclosed herein is a system and method for determining whether a medical device inserted into a patient has deviated from a target advancement path and has entered the vessel of the patient based on one or more signals from the medical device.

SUMMARY

Briefly summarized, some embodiments disclosed herein are directed to systems, apparatuses and methods for obtaining three-dimensional (3D) information (reflected light) corresponding to a trajectory and/or shape of a medical instrument, such as a catheter, a guidewire, or a stylet, during advancement through a vasculature of a patient, and determining malposition of the medical instrument within a vessel of the patient, such as the Azygos vein. In some embodiments, the system is a fiber optic shape sensing system and methods thereof, configured to provide confirmation of tip placement or information passed/interpreted as an electrical signal. Some embodiments combine the fiber optic shape sensing functionality with one or more of intravascular electrocardiogram (ECG) monitoring, impedance/conductance sensing and blood flow directional detection. Although the examples herein are with respect to malposition into the Azygos vein, the invention described herein is not so limited. It should be appreciated that the invention described herein can be used to detect malposition of a medical device in any number of vessels and locations in a patient, and is not intended to be specific to malposition into the Azygos vein.

More particularly, in some embodiments, the medical instrument includes a multi-core optical fiber, with each core fiber of the multi-core optical fiber is configured with an array of sensors (reflective gratings), which are spatially distributed over a prescribed length of the core fiber to generally sense external strain on those regions of the core fiber occupied by the sensor. The multi-core optical fiber is configured to receive broadband light from a console during advancement through the vasculature of a patient, where the broadband light propagates along at least a partial distance of the multi-core optical fiber toward the distal end. Given that each sensor positioned along the same core fiber is configured to reflect light of a different, specific spectral width, the array of sensors enable distributed measurements throughout the prescribed length of the multi-core optical fiber. These distributed measurements may include wavelength shifts having a correlation with strain experienced by the sensor.

The reflected light from the sensors (reflective gratings) within each core fiber of the multi-core optical fiber is returned from the medical instrument for processing by the console. The physical state of the medical instrument may be ascertained based on analytics of the wavelength shifts of the reflected light. For example, the strain caused through bending of the medical instrument, and hence angular modification of each core fiber, causes different degrees of deformation. The different degrees of deformation alters the shape of the sensors (reflective grating) positioned on the core fiber, which may cause variations (shifts) in the wavelength of the reflected light from the sensors positioned on each core fiber within the multi-core optical fiber, as shown in FIGS. 2-5B and 7A-13 .

Specific embodiments of the disclosure include utilization of a stylet featuring a multi-core optical fiber and a conductive medium that collectively operate for tracking placement of a catheter or other medical device within a body of a patient. The stylet is configured to return information for use in identifying its physical state (e.g., shape length, shape, and/or form) of (i) a portion of the stylet (e.g., tip, segment of stylet, etc.) or a portion of a catheter inclusive of at least a portion of the stylet (e.g., tip, segment of catheter, etc.) or (ii) the entirety or a substantial portion of the stylet or catheter within the body of a patient (hereinafter, described as the “physical state of the stylet” or the “physical state of the catheter”). According to one embodiment of the disclosure, the returned information may be obtained from reflected light signals of different spectral widths, where each reflected light signal corresponds to a portion of broadband incident light propagating along a core of the multi-core optical fiber (hereinafter, “core fiber”) that is reflected back over the core fiber by a particular sensor located on the core fiber. One illustrative example of the returned information may pertain to a change in signal characteristics of the reflected light signal returned from the sensor, where wavelength shift is correlated to (mechanical) strain on the core fiber.

In some embodiments in which the stylet includes a multi-core optical fiber, each core fiber utilizes a plurality of sensors and each sensor is configured to reflect a different spectral range of the incident light (e.g., different light frequency range). Based on the type and degree of strain asserted on each core fiber, the sensors associated with that core fiber may alter (shift) the wavelength of the reflected light to convey the type and degree of stain on that core fiber at those locations of the stylet occupied by the sensors. The sensors are spatially distributed at various locations of the core fiber between a proximal end and a distal end of the stylet so that shape sensing of the stylet may be conducted based on analytics of the wavelength shifts. Herein, the shape sensing functionality is paired with the ability to simultaneously pass an electrical signal through the same member (stylet) through conductive medium included as part of the stylet.

More specifically, in some embodiments each core fiber of the multi-core optical fiber is configured with an array of sensors, which are spatially distributed over a prescribed length of the core fiber to generally sense external strain those regions of the core fiber occupied by the sensor. Given that each sensor positioned along the same core fiber is configured to reflect light of a different, specific spectral width, the array of sensors enable distributed measurements throughout the prescribed length of the multi-core optical fiber. These distributed measurements may include wavelength shifts having a correlation with strain experienced by the sensor.

According to one embodiment of the disclosure, each sensor may operate as a reflective grating such as a fiber Bragg grating (FBG), namely an intrinsic sensor corresponding to a permanent, periodic refractive index change inscribed into the core fiber. Stated differently, the sensor operates as a light reflective mirror for a specific spectral width (e.g., a specific wavelength or specific range of wavelengths). As a result, as broadband incident light is supplied by an optical light source and propagates through a particular core fiber, upon reaching a first sensor of the distributed array of sensors for that core fiber, light of a prescribed spectral width associated with the first sensor is reflected back to an optical receiver within a console, including a display and the optical light source. The remaining spectrum of the incident light continues propagation through the core fiber toward a distal end of the stylet. The remaining spectrum of the incident light may encounter other sensors from the distributed array of sensors, where each of these sensors is fabricated to reflect light with different specific spectral widths to provide distributed measurements, as described above.

During operation, multiple light reflections (also referred to as “reflected light signals”) are returned to the console from each of the plurality of core fibers of the multi-core optical fiber. Each reflected light signal may be uniquely associated with a different spectral width. Information associated with the reflected light signals may be used to determine a three-dimensional representation of the physical state of the stylet within the body of a patient. Herein, the core fibers are spatially separated with the cladding of the multi-mode optical fiber and each core fiber is configured to separately return light of different spectral widths (e.g., specific light wavelength or a range of light wavelengths) reflected from the distributed array of sensors fabricated in each of the core fibers. A comparison of detected shifts in wavelength of the reflected light returned by a center core fiber (operating as a reference) and the surrounding, periphery core fibers may be used to determine the physical state of the stylet.

During vasculature insertion and advancement of the catheter, the clinician may rely on the console to visualize a current physical state (e.g., shape) of a catheter guided by the stylet to avoid potential path deviations. As the periphery core fibers reside at spatially different locations within the cladding of the multi-mode optical fiber, changes in angular orientation (such as bending with respect to the center core fiber, etc.) of the stylet imposes different types (e.g., compression or tension) and degrees of strain on each of the periphery core fibers as well as the center core fiber. The different types and/or degree of strain may cause the sensors of the core fibers to apply different wavelength shifts, which can be measured to extrapolate the physical state of the stylet (catheter).

Embodiments of the disclosure may include a combination of one or more of the methodologies to determine when a body of implementation (e.g., catheter, guidewire, and/or stylet) has deviated from its target trajectory (e.g., into the right atrium) and instead into an undesired location (e.g., the Azygos vein). Certain embodiments of the disclosure pertain to distal tip location detection using fiber optic shape sensing such that deviation of the body of implementation into the negative-Z plane (dorsal movement of the body of implementation) can be detected and identified using analysis of reflected light through a multi-core optical fiber as discussed below. For example, the use of fiber optic shape sensing may analyze the reflected light in comparison to predetermined anatomical angles, deviation from an identified reference plane (with identified anterior/posterior orientation), and/or deviation from a predetermined anatomical frame.

Further embodiments of the disclosure pertain to the use of fiber optic shape sensing to detect fluctuation of the body of implementation. For example, deviation of the advancement of the body of implementation out of the SVC into the Azygos vein is identified via a reduction in fluctuations in the body of implementation. Additionally, intravascular ECG monitoring may be combined with either or both of the fiber optic shape sensing methodologies referenced above to detect deviation of the advancement of the body of implementation into the Azygos vein as the detected P-wave of the intravascular ECG decreases in slightly in amplitude even as the body of implementation is advanced towards the sinoatrial (SA) node. Additionally, or in the alternative, impedance/conductance sensing may be combined with either or both of the fiber optic shape sensing methodologies and, optionally, the ECG intravascular ECG monitoring to detect deviation of the advancement of the body of implementation into the Azygos vein. For instance, as the body of implementation deviates into the Azygos vein the smaller diameter vessel is characterized by a varied impedance/conductance.

In yet other embodiments, the direction of the blood flow may be utilized in combination with any of the fiber optic shape sensing methodologies, intravascular ECG monitoring and/or impedance/conductance sensing referenced above. For instance, as the body of implementation deviates into the Azygos vein, the flow of blood will change from in-line with the advancement of the body of implementation to against the advancement of the body of implementation, which may be detected using pulse oximetry and/or blood flow Doppler. For instance, detection using pulse oximetry includes measurement and analysis of the oxygen levels within the blood as the body of implementation advances through the vasculature. Specifically, analysis of the oxygen levels may vary from vessel to vessel such that detection of deviation of the distal tip of the body of implementation into the Azygos vein may be detected when the measured oxygen level decreases when the distal tip is in the heart. Specifically, the oxygen level may decrease as the distal tip of the body of implementation advances from a larger vessel (SVC) to a smaller vessel (Azygos vein).

Some embodiments herein disclose a medical device system for detecting malposition of a medical device within a vessel of a patient, such as an Azygos vein, the system including the medical device comprising a multi-core optical fiber having a plurality of core fibers, each of the plurality of core fibers including a plurality of sensors distributed along a longitudinal length of a corresponding core fiber and each sensor of the plurality of sensors being configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber and a console. The console includes one or more processors and a non-transitory computer-readable medium having stored thereon logic, when executed by the one or more processors, causes operations including providing a broadband incident light signal to the multi-core optical fiber, receiving reflected light signals of different spectral widths of the broadband incident light reflected by each of the plurality of sensors, processing the reflected light signals associated with the plurality of core fibers, and determining whether the medical device has entered the Azygos vein of the patient based on the reflected light signals.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on a shape of the medical device indicated by the reflected light signals. In some embodiments, the shape of the medical device is indicated by the reflected light signals is utilized as input to a machine-learning configured to process the input and provide a result indicating a confidence level as to whether the shape of the medical device indicates entry into the Azygos vein of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based a result of heuristics performed on the shape of the medical device indicated by the reflected light signals. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on an amount of fluctuation of the medical device indicated by the reflected light signals.

In particular embodiments, the amount of fluctuation of the medical device is an amount of fluctuation at a distal tip of the medical device. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and impedance sensing of advancement of the medical device through a vasculature of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on (i) the shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, and (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and detection of a direction of blood flow within a portion of a vasculature of the patient in which the medical device is currently disposed. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and one or more of (i) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (ii) impedance sensing of the advancement of the medical device through the vasculature of the patient, or (iii) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on (i) the shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient, and (iv) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.

In particular embodiments, the different types of strain include compression and tension. In other embodiments, the medical device includes an elongated shape and is inserted into a vasculature of the body of the patient. In some embodiments, the medical device is a stylet removably inserted into a lumen of a catheter assembly for placement of a distal tip of the catheter assembly in a superior vena cava of the vasculature. In yet other embodiments, at least two of the plurality of core fibers to experience different types of strain in response to changes in an orientation of the multi-core optical fiber. In yet further embodiments, each of the plurality of sensors is a reflective grating, where each reflective grating alters its reflected light signal by applying a wavelength shift dependent on a strain experienced by the reflective grating.

Further embodiments relate to a method for placing a medical device into a body of a patient, the method comprising providing a broadband incident light signal to a multi-core optical fiber included within the medical device, wherein the multi-core optical fiber includes a plurality of core fibers, each of the plurality of core fibers including a plurality of reflective gratings distributed along a longitudinal length of a corresponding core fiber and each of the plurality of reflective gratings being configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber, receiving reflected light signals of different spectral widths of the broadband incident light reflected by each of a plurality of reflective gratings, processing the reflected light signals associated with the plurality of core fibers, and determining whether the medical device has entered the Azygos vein of the patient based on the reflected light signals.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on a shape of the medical device indicated by the reflected light signals. In some embodiments, the shape of the medical device is indicated by the reflected light signals is utilized as input to a machine-learning configured to process the input and provide a result indicating a confidence level as to whether the shape of the medical device indicates entry into the Azygos vein of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based a result of heuristics performed on the shape of the medical device indicated by the reflected light signals. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on an amount of fluctuation of the medical device indicated by the reflected light signals.

In particular embodiments, the amount of fluctuation of the medical device is an amount of fluctuation at a distal tip of the medical device. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and impedance sensing of advancement of the medical device through a vasculature of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on (i) the shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, and (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and detection of a direction of blood flow within a portion of a vasculature of the patient in which the medical device is currently disposed. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and one or more of (i) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (ii) impedance sensing of the advancement of the medical device through the vasculature of the patient, or (iii) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on (i) the shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient, and (iv) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.

In particular embodiments, the different types of strain include compression and tension. In other embodiments, the medical device includes an elongated shape and is inserted into a vasculature of the body of the patient. In some embodiments, the medical device is a stylet removably inserted into a lumen of a catheter assembly for placement of a distal tip of the catheter assembly in a superior vena cava of the vasculature. In yet other embodiments, at least two of the plurality of core fibers to experience different types of strain in response to changes in an orientation of the multi-core optical fiber. In yet further embodiments, each of the plurality of sensors is a reflective grating, where each reflective grating alters its reflected light signal by applying a wavelength shift dependent on a strain experienced by the reflective grating.

Some embodiments of disclose a non-transitory computer-readable medium having stored thereon logic that, when executed by the one or more processors, causes operations. The operations include providing a broadband incident light signal to a multi-core optical fiber included within the medical device, wherein the multi-core optical fiber includes a plurality of core fibers, each of the plurality of core fibers including a plurality of reflective gratings distributed along a longitudinal length of a corresponding core fiber and each reflective grating of the plurality of reflective gratings being configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber, receiving reflected light signals of different spectral widths of the broadband incident reflected each of the plurality of reflective gratings, processing the reflected light signals associated with the plurality of core fibers, and determining whether the medical device has entered the Azygos vein of the patient based on the reflected light signals.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on a shape of the medical device indicated by the reflected light signals. In some embodiments, the shape of the medical device is indicated by the reflected light signals is utilized as input to a machine-learning configured to process the input and provide a result indicating a confidence level as to whether the shape of the medical device indicates entry into the Azygos vein of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based a result of heuristics performed on the shape of the medical device indicated by the reflected light signals. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on an amount of fluctuation of the medical device indicated by the reflected light signals.

In particular embodiments, the amount of fluctuation of the medical device is an amount of fluctuation at a distal tip of the medical device. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and impedance sensing of advancement of the medical device through a vasculature of the patient. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on (i) the shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, and (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and detection of a direction of blood flow within a portion of a vasculature of the patient in which the medical device is currently disposed. In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on the shape of the medical device indicated by the reflected light signals and one or more of (i) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (ii) impedance sensing of the advancement of the medical device through the vasculature of the patient, or (iii) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.

In some embodiments, the determining operation determines whether the medical device has entered the Azygos vein is based on (i) the shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient, and (iv) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.

In particular embodiments, the different types of strain include compression and tension. In other embodiments, the medical device includes an elongated shape and is inserted into a vasculature of the body of the patient. In some embodiments, the medical device is a stylet removably inserted into a lumen of a catheter assembly for placement of a distal tip of the catheter assembly in a superior vena cava of the vasculature. In yet other embodiments, at least two of the plurality of core fibers to experience different types of strain in response to changes in an orientation of the multi-core optical fiber. In yet further embodiments, each of the plurality of sensors is a reflective grating, where each reflective grating alters its reflected light signal by applying a wavelength shift dependent on a strain experienced by the reflective grating.

These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and following description, which disclose particular embodiments of such concepts in greater detail.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

FIG. 1A is an illustrative embodiment of a medical instrument monitoring system including a medical instrument with optic shape sensing and fiber optic-based oximetry capabilities in accordance with some embodiments;

FIG. 1B is an alternative illustrative embodiment of the medical instrument monitoring system 100 in accordance with some embodiments;

FIG. 2 is an exemplary embodiment of a structure of a section of the multi-core optical fiber included within the stylet 120 of FIG. 1A in accordance with some embodiments;

FIG. 3A is a first exemplary embodiment of the stylet of FIG. 1A supporting both an optical and electrical signaling in accordance with some embodiments;

FIG. 3B is a cross sectional view of the stylet of FIG. 3A in accordance with some embodiments;

FIG. 4A is a second exemplary embodiment of the stylet of FIG. 1B in accordance with some embodiments;

FIG. 4B is a cross sectional view of the stylet of FIG. 4A in accordance with some embodiments;

FIG. 5A is an elevation view of a first illustrative embodiment of a catheter including integrated tubing, a diametrically disposed septum, and micro-lumens formed within the tubing and septum in accordance with some embodiments;

FIG. 5B is a perspective view of the first illustrative embodiment of the catheter of FIG. 5A including core fibers installed within the micro-lumens in accordance with some embodiments;

FIGS. 6A-6B are flowcharts of the methods of operations conducted by the medical instrument monitoring system of FIGS. 1A-1B to achieve optic 3D shape sensing in accordance with some embodiments;

FIG. 7A is an exemplary embodiment of the medical instrument monitoring system of FIG. 1 during operation and insertion of the catheter into a patient in accordance with some embodiments;

FIG. 7B is a detailed view of the stylet of FIG. 7A in the Superior Vena Cava (SVC) advancing toward the right atrium of the patient in accordance with some embodiments;

FIG. 8 is a first illustration of a stylet advancing through a patient's vasculature toward the right atrium of the patient's heart in accordance with some embodiments;

FIG. 9 is a second illustration of a stylet advancing through a patient's vasculature toward the right atrium of the patient's heart in accordance with some embodiments;

FIGS. 10A-10C are illustrations depicting an electrode configuration that provides for acquisition of endovascular ECG data in accordance some embodiments;

FIG. 11 is an illustration of an exemplary peripherally inserted central catheter in accordance with some embodiments; and

FIG. 12 is an illustration of a system utilizing a second embodiment of a peripherally inserted central in conjunction with two electrode pads in accordance with some embodiments.

DETAILED DESCRIPTION

Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein.

Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

With respect to “proximal,” a “proximal portion” or a “proximal end portion” of, for example, a probe disclosed herein includes a portion of the probe intended to be near a clinician when the probe is used on a patient. Likewise, a “proximal length” of, for example, the probe includes a length of the probe intended to be near the clinician when the probe is used on the patient. A “proximal end” of, for example, the probe includes an end of the probe intended to be near the clinician when the probe is used on the patient. The proximal portion, the proximal end portion, or the proximal length of the probe can include the proximal end of the probe; however, the proximal portion, the proximal end portion, or the proximal length of the probe need not include the proximal end of the probe. That is, unless context suggests otherwise, the proximal portion, the proximal end portion, or the proximal length of the probe is not a terminal portion or terminal length of the probe.

With respect to “distal,” a “distal portion” or a “distal end portion” of, for example, a probe disclosed herein includes a portion of the probe intended to be near or in a patient when the probe is used on the patient. Likewise, a “distal length” of, for example, the probe includes a length of the probe intended to be near or in the patient when the probe is used on the patient. A “distal end” of, for example, the probe includes an end of the probe intended to be near or in the patient when the probe is used on the patient. The distal portion, the distal end portion, or the distal length of the probe can include the distal end of the probe; however, the distal portion, the distal end portion, or the distal length of the probe need not include the distal end of the probe. That is, unless context suggests otherwise, the distal portion, the distal end portion, or the distal length of the probe is not a terminal portion or terminal length of the probe.

The term “logic” may be representative of hardware, firmware or software that is configured to perform one or more functions. As hardware, the term logic may refer to or include circuitry having data processing and/or storage functionality. Examples of such circuitry may include, but are not limited or restricted to a hardware processor (e.g., microprocessor, one or more processor cores, a digital signal processor, a programmable gate array, a microcontroller, an application specific integrated circuit “ASIC”, etc.), a semiconductor memory, or combinatorial elements.

Additionally, or in the alternative, the term logic may refer to or include software such as one or more processes, one or more instances, Application Programming Interface(s) (API), subroutine(s), function(s), applet(s), servlet(s), routine(s), source code, object code, shared library/dynamic link library (dll), or even one or more instructions. This software may be stored in any type of a suitable non-transitory storage medium, or transitory storage medium (e.g., electrical, optical, acoustical or other form of propagated signals such as carrier waves, infrared signals, or digital signals). Examples of a non-transitory storage medium may include, but are not limited or restricted to a programmable circuit; non-persistent storage such as volatile memory (e.g., any type of random access memory “RAM”); or persistent storage such as non-volatile memory (e.g., read-only memory “ROM”, power-backed RAM, flash memory, phase-change memory, etc.), a solid-state drive, hard disk drive, an optical disc drive, or a portable memory device. As firmware, the logic may be stored in persistent storage.

Referring to FIG. 1A, an illustrative embodiment of a medical instrument monitoring system including a medical instrument with optic shape sensing and fiber optic-based oximetry capabilities is shown in accordance with some embodiments. As shown, the system 100 generally includes a console 110 and a stylet assembly 119 communicatively coupled to the console 110. For this embodiment, the stylet assembly 119 includes an elongate probe (e.g., stylet) 120 on its distal end 122 and a console connector 133 on its proximal end 124, where the stylet 120 is configured to advance within a patient vasculature either through, or in conjunction with, a catheter 195. The console connector 133 enables the stylet assembly 119 to be operably connected to the console 110 via an interconnect 145 including one or more optical fibers 147 (hereinafter, “optical fiber(s)”) and a conductive medium terminated by a single optical/electric connector 146 (or terminated by dual connectors. Herein, the connector 146 is configured to engage (mate) with the console connector 133 to allow for the propagation of light between the console 110 and the stylet assembly 119 as well as the propagation of electrical signals from the stylet 120 to the console 110.

An exemplary implementation of the console 110 includes a processor 160, a memory 165, a display 170 and optical logic 180, although it is appreciated that the console 110 can take one of a variety of forms and may include additional components (e.g., power supplies, ports, interfaces, etc.) that are not directed to aspects of the disclosure. An illustrative example of the console 110 is illustrated in U.S. Publication No. 2019/0237902, the entire contents of which are incorporated by reference herein. The processor 160, with access to the memory 165 (e.g., non-volatile memory or non-transitory, computer-readable medium), is included to control functionality of the console 110 during operation. As shown, the display 170 may be a liquid crystal diode (LCD) display integrated into the console 110 and employed as a user interface to display information to the clinician, especially during a catheter placement procedure (e.g., cardiac catheterization). In another embodiment, the display 170 may be separate from the console 110. Although not shown, a user interface is configured to provide user control of the console 110.

For both of these embodiments, the content depicted by the display 170 may change according to which mode the stylet 120 is configured to operate: optical, TLS, ECG, or another modality. In TLS mode, the content rendered by the display 170 may constitute a two-dimensional (2D) or three-dimensional (3D) representation of the physical state (e.g., length, shape, form, and/or orientation) of the stylet 120 computed from characteristics of reflected light signals 150 returned to the console 110. The reflected light signals 150 constitute light of a specific spectral width of broadband incident light 155 reflected back to the console 110. According to one embodiment of the disclosure, the reflected light signals 150 may pertain to various discrete portions (e.g., specific spectral widths) of broadband incident light 155 transmitted from and sourced by the optical logic 180, as described below

According to one embodiment of the disclosure, an activation control 126, included on the stylet assembly 119, may be used to set the stylet 120 into a desired operating mode and selectively alter operability of the display 170 by the clinician to assist in medical device placement. For example, based on the modality of the stylet 120, the display 170 of the console 110 can be employed for optical modality-based guidance during catheter advancement through the vasculature or TLS modality to determine the physical state (e.g., length, form, shape, orientation, etc.) of the stylet 120. In one embodiment, information from multiple modes, such as optical, TLS or ECG for example, may be displayed concurrently (e.g., at least partially overlapping in time).

Referring still to FIG. 1A, the optical logic 180 is configured to support operability of the stylet assembly 119 and enable the return of information to the console 110, which may be used to determine the physical state associated with the stylet 120 along with monitored electrical signals such as ECG signaling via an electrical signaling logic 181 that supports receipt and processing of the received electrical signals from the stylet 120 (e.g., ports, analog-to-digital conversion logic, etc.). The physical state of the stylet 120 may be based on changes in characteristics of the reflected light signals 150 received at the console 110 from the stylet 120. The characteristics may include shifts in wavelength caused by strain on certain regions of the core fibers integrated within an optical fiber core 135 positioned within or operating as the stylet 120, as shown below. As discussed herein, the optical fiber core 135 may be comprised of core fibers 137 ₁-137 _(M) (M=1 for a single core, and M≥2 for a multi-core), where the core fibers 137 ₁-137 _(M) may collectively be referred to as core fiber(s) 137. Unless otherwise specified or the instant embodiment requires an alternative interpretation, embodiments discussed herein will refer to a multi-core optical fiber 135. From information associated with the reflected light signals 150, the console 110 may determine (through computation or extrapolation of the wavelength shifts) the physical state of the stylet 120, and also that of the catheter 195 configured to receive the stylet 120.

According to one embodiment of the disclosure, as shown in FIG. 1A, the optical logic 180 may include a light source 182 and an optical receiver 184. The light source 182 is configured to transmit the incident light 155 (e.g., broadband) for propagation over the optical fiber(s) 147 included in the interconnect 145, which are optically connected to the multi-core optical fiber core 135 within the stylet 120. In one embodiment, the light source 182 is a tunable swept laser, although other suitable light sources can also be employed in addition to a laser, including semi-coherent light sources, LED light sources, etc.

The optical receiver 184 is configured to: (i) receive returned optical signals, namely reflected light signals 150 received from optical fiber-based reflective gratings (sensors) fabricated within each core fiber of the multi-core optical fiber 135 deployed within the stylet 120, and (ii) translate the reflected light signals 150 into reflection data (from repository 192), namely data in the form of electrical signals representative of the reflected light signals including wavelength shifts caused by strain. The reflected light signals 150 associated with different spectral widths may include reflected light signals 151 provided from sensors positioned in the center core fiber (reference) of the multi-core optical fiber 135 and reflected light signals 152 provided from sensors positioned in the periphery core fibers of the multi-core optical fiber 135, as described below. Herein, the optical receiver 184 may be implemented as a photodetector, such as a positive-intrinsic-negative “PIN” photodiode, avalanche photodiode, or the like.

As shown, both the light source 182 and the optical receiver 184 are operably connected to the processor 160, which governs their operation. Also, the optical receiver 184 is operably coupled to provide the reflection data (from repository 192) to the memory 165 for storage and processing by reflection data classification logic 190. The reflection data classification logic 190 may be configured to: (i) identify which core fibers pertain to which of the received reflection data (from repository 192) and (ii) segregate the reflection data stored with a repository 192 provided from reflected light signals 150 pertaining to similar regions of the stylet 120 or spectral widths into analysis groups. The reflection data for each analysis group is made available to shape sensing logic 194 for analytics.

According to one embodiment of the disclosure, the shape sensing logic 194 is configured to compare wavelength shifts measured by sensors deployed in each periphery core fiber at the same measurement region of the stylet 120 (or same spectral width) to the wavelength shift at a center core fiber of the multi-core optical fiber 135 positioned along central axis and operating as a neutral axis of bending. From these analytics, the shape sensing logic 194 may determine the shape the core fibers have taken in 3D space and may further determine the current physical state of the catheter 195 in 3D space for rendering on the display 170.

According to one embodiment of the disclosure, the shape sensing logic 194 may generate a rendering of the current physical state of the stylet 120 (and potentially the catheter 195), based on heuristics or run-time analytics. For example, the shape sensing logic 194 may be configured in accordance with machine-learning techniques to access a data store (library) with pre-stored data (e.g., images, etc.) pertaining to different regions of the stylet 120 (or catheter 195) in which reflected light from core fibers have previously experienced similar or identical wavelength shifts. From the pre-stored data, the current physical state of the stylet 120 (or catheter 195) may be rendered. Alternatively, as another example, the shape sensing logic 194 may be configured to determine, during run-time, changes in the physical state of each region of the multi-core optical fiber 135 based on at least: (i) resultant wavelength shifts experienced by different core fibers within the optical fiber 135, and (ii) the relationship of these wavelength shifts generated by sensors positioned along different periphery core fibers at the same cross-sectional region of the multi-core optical fiber 135 to the wavelength shift generated by a sensor of the center core fiber at the same cross-sectional region. It is contemplated that other processes and procedures may be performed to utilize the wavelength shifts as measured by sensors along each of the core fibers within the multi-core optical fiber 135 to render appropriate changes in the physical state of the stylet 120 (and/or catheter 195), especially to enable guidance of the stylet 120, when positioned at a distal tip of the catheter 195, within the vasculature of the patient and at a desired destination within the body.

The console 110 may further include electrical signaling logic 181, which is positioned to receive one or more electrical signals from the stylet 120. The stylet 120 is configured to support both optical connectivity as well as electrical connectivity. The electrical signaling logic 181 receives the electrical signals (e.g., ECG signals) from the stylet 120 via the conductive medium. The electrical signals may be processed by electrical signal logic 196, executed by the processor 160, to determine ECG waveforms for display.

Additionally, the console 110 includes a fluctuation logic 198 that is configured to analyze at least a subset of the wavelength shifts measured by sensors deployed in each of the core fibers 137. In particular, the fluctuation logic 198 is configured to analyze wavelength shifts measured by sensors of core fibers 137, where such corresponds to an analysis of the fluctuation of the distal tip of the stylet 120 (or “tip fluctuation analysis”). In some embodiments, the fluctuation logic 198 measures analyzes the wavelength shifts measured by sensors at a distal end of the core fibers 137. The tip fluctuation analysis includes at least a correlation of detected movements of the distal tip of the stylet 120 (or other medical device or instrument) with experiential knowledge comprising previously detected movements (fluctuations), and optionally, other current measurements such as ECG signals. The experiential knowledge may include previously detected movements in various locations within the vasculature (e.g., SVC, Inferior Vena Cava (IVC), right atrium, azygos vein, other blood vessels such as arteries and veins) under normal, healthy conditions and in the presence of defects (e.g., vessel constriction, vasospasm, vessel occlusion, etc.). Thus, the tip fluctuation analysis may result in a confirmation of tip location and/or detection of a defect affecting a blood vessel.

It should be noted that the fluctuation logic 198 need not perform the same analyses as the shape sensing logic 194. For instance, the shape sensing logic 194 determines a 3D shape of the stylet 120 by comparing wavelength shifts in outer core fibers of a multi-core optical fiber to a center, reference core fiber. The fluctuation logic 198 may instead correlate the wavelength shifts to previously measured wavelength shifts and optionally other current measurements without distinguishing between wavelength shifts of outer core fibers and a center, reference core fiber as the tip fluctuation analysis need not consider direction or shape within a 3D space.

In some embodiments, e.g., those directed at tip location confirmation, the analysis of the fluctuation logic 198 may utilize electrical signals (e.g., ECG signals) measured by the electrical signaling logic 181. For example, the fluctuation logic 198 may compare the movements of a subsection of the stylet 120 (e.g., the distal tip) with electrical signals indicating impulses of the heart (e.g., the heartbeat). Such a comparison may reveal whether the distal tip is within the SVC or the right atrium based on how closely the movements correspond to a rhythmic heartbeat.

In various embodiments, a display and/or alert may be generated based on the fluctuation analysis. For instance, the fluctuation logic 198 may generate a graphic illustrating the detected fluctuation compared to previously detected tip fluctuations and/or the anatomical movements of the patient body such as rhythmic pulses of the heart and/or expanding and contracting of the lungs. In one embodiment, such a graphic may include a dynamic visualization of the present medical device moving in accordance with the detected fluctuations adjacent to a secondary medical device moving in accordance with previously detected tip fluctuations. In some embodiments, the location of a subsection of the medical device may be obtained from the shape sensing logic 194 and the dynamic visualization may be location-specific (e.g., such that the previously detected fluctuations illustrate expected fluctuations for the current location of the subsection). In alternative embodiments, the dynamic visualization may illustrate a comparison of the dynamic movements of the subsection to one or more subsections moving in accordance with previously detected fluctuations of one or more defects affecting the blood vessel.

According to one embodiment of the disclosure, the fluctuation logic 198 may determine whether movements of one or more subsections of the stylet 120 indicate a location of a particular subsection of the stylet 120 or a defect affecting a blood vessel and, as a result, of the catheter 195, based on heuristics or run-time analytics. For example, the fluctuation logic 198 may be configured in accordance with machine-learning techniques to access a data store (library) with pre-stored data (e.g., experiential knowledge of previously detected tip fluctuation data, etc.) pertaining to different regions (subsections) of the stylet 120. Specifically, such an embodiment may include processing of a machine-learning model trained using the experiential knowledge, where the detected fluctuations serve as input to the trained model and processing of the trained model results in a determination as to how closely the detected fluctuations correlate to one or more locations within the vasculature of the patient and/or one or more defects affecting a blood vessel.

In some embodiments, the fluctuation logic 198 may be configured to determine, during run-time, whether movements of one or more subsections of the stylet 120 (and the catheter 195) indicate a location of a particular subsection of the stylet 120 or a defect affecting a blood vessel, based on at least (i) resultant wavelength shifts experienced by the core fibers 137 within the one or more subsections, and (ii) the correlation of these wavelength shifts generated by sensors positioned along different core fibers at the same cross-sectional region of the stylet 120 (or the catheter 195) to previously detected wavelength shifts generated by corresponding sensors in a core fiber at the same cross-sectional region. It is contemplated that other processes and procedures may be performed to utilize the wavelength shifts as measured by sensors along each of the core fibers 137 to render appropriate movements in the distal tip of the stylet 120 and/or the catheter 195.

Referring to FIG. 1B, an alternative exemplary embodiment of a medical instrument monitoring system 100 is shown. Herein, the medical instrument monitoring system 100 features a console 110 and a medical instrument 130 communicatively coupled to the console 110. For this embodiment, the medical instrument 130 corresponds to a catheter, which features an integrated tubing with two or more lumen extending between a proximal end 131 and a distal end 132 of the integrated tubing. The integrated tubing (sometimes referred to as “catheter tubing”) is in communication with one or more extension legs 140 via a bifurcation hub 142. An optical-based catheter connector 144 may be included on a proximal end of at least one of the extension legs 140 to enable the catheter 130 to operably connect to the console 110 via an interconnect 145 or another suitable component. Herein, the interconnect 145 may include a connector 146 that, when coupled to the optical-based catheter connector 144, establishes optical connectivity between one or more optical fibers 147 (hereinafter, “optical fiber(s)”) included as part of the interconnect 145 and core fibers 137 deployed within the catheter 130 and integrated into the tubing. Alternatively, a different combination of connectors, including one or more adapters, may be used to optically connect the optical fiber(s) 147 to the core fibers 137 within the catheter 130. The core fibers 137 deployed within the catheter 130 as illustrated in FIG. 1B include the same characteristics and perform the same functionalities as the core fibers 137 deployed within the stylet 120 of FIG. 1A.

The optical logic 180 is configured to support graphical rendering of the catheter 130, most notably the integrated tubing of the catheter 130, based on characteristics of the reflected light signals 150 received from the catheter 130. The characteristics may include shifts in wavelength caused by strain on certain regions of the core fibers 137 integrated within (or along) a wall of the integrated tubing, which may be used to determine (through computation or extrapolation of the wavelength shifts) the physical state of the catheter 130, notably its integrated tubing or a portion of the integrated tubing such as a tip or distal end of the tubing to read fluctuations (real-time movement) of the tip (or distal end).

More specifically, the optical logic 180 includes a light source 182. The light source 182 is configured to transmit the broadband incident light 155 for propagation over the optical fiber(s) 147 included in the interconnect 145, which are optically connected to multiple core fibers 137 within the catheter tubing. Herein, the optical receiver 184 is configured to: (i) receive returned optical signals, namely reflected light signals 150 received from optical fiber-based reflective gratings (sensors) fabricated within each of the core fibers 137 deployed within the catheter 130, and (ii) translate the reflected light signals 150 into reflection data (from repository 192), namely data in the form of electrical signals representative of the reflected light signals including wavelength shifts caused by strain. The reflected light signals 150 associated with different spectral widths include reflected light signals 151 provided from sensors positioned in the center core fiber (reference) of the catheter 130 and reflected light signals 152 provided from sensors positioned in the outer core fibers of the catheter 130, as described below.

As noted above, the shape sensing logic 194 is configured to compare wavelength shifts measured by sensors deployed in each outer core fiber at the same measurement region of the catheter (or same spectral width) to the wavelength shift at the center core fiber positioned along central axis and operating as a neutral axis of bending. From these analytics, the shape sensing logic 190 may determine the shape the core fibers have taken in 3D space and may further determine the current physical state of the catheter 130 in 3D space for rendering on the display 170.

According to one embodiment of the disclosure, the shape sensing logic 194 may generate a rendering of the current physical state of the catheter 130, especially the integrated tubing, based on heuristics or run-time analytics. For example, the shape sensing logic 194 may be configured in accordance with machine-learning techniques to access a data store (library) with pre-stored data (e.g., images, etc.) pertaining to different regions of the catheter 130 in which the core fibers 137 experienced similar or identical wavelength shifts. From the pre-stored data, the current physical state of the catheter 130 may be rendered. Alternatively, as another example, the shape sensing logic 194 may be configured to determine, during run-time, changes in the physical state of each region of the catheter 130, notably the tubing, based on at least (i) resultant wavelength shifts experienced by the core fibers 137 and (ii) the relationship of these wavelength shifts generated by sensors positioned along different outer core fibers at the same cross-sectional region of the catheter 130 to the wavelength shift generated by a sensor of the center core fiber at the same cross-sectional region. It is contemplated that other processes and procedures may be performed to utilize the wavelength shifts as measured by sensors along each of the core fibers 137 to render appropriate changes in the physical state of the catheter 130.

Referring to FIG. 2 , an exemplary embodiment of a structure of a section of the multi-core optical fiber included within the stylet 120 of FIG. 1A is shown in accordance with some embodiments. The multi-core optical fiber section 200 of the multi-core optical fiber 135 depicts certain core fibers 137 ₁-137 _(M) (M≥2, M=4 as shown, see FIG. 3A) along with the spatial relationship between sensors (e.g., reflective gratings) 210 ₁₁-210 _(NM) (N≥2; M≥2) present within the core fibers 137 ₁-137 _(M), respectively. As noted above, the core fibers 137 ₁-137 _(M) may be collectively referred to as “the core fibers 137.”

As shown, the section 200 is subdivided into a plurality of cross-sectional regions 220 ₁-220 _(N), where each cross-sectional region 220 ₁-220 _(N) corresponds to reflective gratings 210 ₁₁-210 ₁₄ . . . 210 _(N1)-210 _(N4). Some or all of the cross-sectional regions 220 ₁ . . . 220 _(N) may be static (e.g., prescribed length) or may be dynamic (e.g., vary in size among the regions 220 ₁ . . . 220 _(N)). A first core fiber 137 ₁ is positioned substantially along a center (neutral) axis 230 while core fiber 137 ₂ may be oriented within the cladding of the multi-core optical fiber 135, from a cross-sectional, front-facing perspective, to be position on “top” the first core fiber 137 ₁. In this deployment, the core fibers 137 ₃ and 137 ₄ may be positioned “bottom left” and “bottom right” of the first core fiber 137 ₁. As examples, FIGS. 3A-4B provides illustrations of such.

Referencing the first core fiber 137 ₁ as an illustrative example, when the stylet 120 is operative, each of the reflective gratings 210 ₁-210 _(N) reflects light for a different spectral width. As shown, each of the gratings 210 _(1i)-210 _(Ni) (1≤i≤M) is associated with a different, specific spectral width, which would be represented by different center frequencies of f₁ . . . f_(N), where neighboring spectral widths reflected by neighboring gratings are non-overlapping according to one embodiment of the disclosure.

Herein, positioned in different core fibers 137 ₂-137 ₃ but along at the same cross-sectional regions 220-220 _(N) of the multi-core optical fiber 135, the gratings 210 ₁₂-210 _(N2) and 210 ₁₃-210 _(N3) are configured to reflect incoming light at same (or substantially similar) center frequency. As a result, the reflected light returns information that allows for a determination of the physical state of the optical fibers 137 (and the stylet 120) based on wavelength shifts measured from the returned, reflected light. In particular, strain (e.g., compression or tension) applied to the multi-core optical fiber 135 (e.g., at least core fibers 137 ₂-137 ₃) results in wavelength shifts associated with the returned, reflected light. Based on different locations, the core fibers 137 ₁-137 ₄ experience different types and degree of strain based on angular path changes as the stylet 120 advances in the patient.

For example, with respect to the multi-core optical fiber section 200 of FIG. 2 , in response to angular (e.g., radial) movement of the stylet 120 is in the left-veering direction, the fourth core fiber 137 ₄ (see FIG. 3A) of the multi-core optical fiber 135 with the shortest radius during movement (e.g., core fiber closest to a direction of angular change) would exhibit compression (e.g., forces to shorten length). At the same time, the third core fiber 137 ₃ with the longest radius during movement (e.g., core fiber furthest from the direction of angular change) would exhibit tension (e.g., forces to increase length). As these forces are different and unequal, the reflected light from reflective gratings 210 _(N2) and 210 _(N3) associated with the core fibers 137 ₂ and 137 ₃ will exhibit different changes in wavelength. The differences in wavelength shift of the reflected light signals 150 can be used to extrapolate the physical configuration of the stylet 120 by determining the degrees of wavelength change caused by compression/tension for each of the periphery fibers (e.g., the second core fiber 137 ₂ and the third core fiber 137 ₃) in comparison to the wavelength of the reference core fiber (e.g., first core fiber 137 ₁) located along the neutral axis 230 of the multi-core optical fiber 135. These degrees of wavelength change may be used to extrapolate the physical state of the stylet 120. The reflected light signals 150 are reflected back to the console 110 via individual paths over a particular core fiber 137 ₁-137 _(M).

Referring to FIG. 3A, a first exemplary embodiment of the stylet of FIG. 1A supporting both an optical and electrical signaling is shown in accordance with some embodiments. Herein, the stylet 120 features a centrally located multi-core optical fiber 135, which includes a cladding 300 and a plurality of core fibers 137 ₁-137 _(M) (M≥2; M=4) residing within a corresponding plurality of lumens 320 ₁-320 _(M). While the multi-core optical fiber 135 is illustrated within four (4) core fibers 137 ₁-137 ₄, a greater number of core fibers 137 ₁-137 _(M) (M>4) may be deployed to provide a more detailed three-dimensional sensing of the physical state (e.g., shape, etc.) of the multi-core optical fiber 135 and the stylet 120 deploying the optical fiber 135.

For this embodiment of the disclosure, the multi-core optical fiber 135 is encapsulated within a concentric braided tubing 310 positioned over a low coefficient of friction layer 335. The braided tubing 310 may feature a “mesh” construction, in which the spacing between the intersecting conductive elements is selected based on the degree of rigidity desired for the stylet 120, as a greater spacing may provide a lesser rigidity, and thereby, a more pliable stylet 120.

According to this embodiment of the disclosure, as shown in FIGS. 3A-3B, the core fibers 137 ₁-137 ₄ include (i) a central core fiber 137 ₁ and (ii) a plurality of periphery core fibers 137 ₂-137 ₄, which are maintained within lumens 320 ₁-320 ₄ formed in the cladding 300. According to one embodiment of the disclosure, one or more of the lumen 320 ₁-320 ₄ may be configured with a diameter sized to be greater than the diameter of the core fibers 137 ₁-137 ₄. By avoiding a majority of the surface area of the core fibers 137 ₁-137 ₄ from being in direct physical contact with a wall surface of the lumens 320 ₁-320 ₄, the wavelength changes to the incident light are caused by angular deviations in the multi-core optical fiber 135 thereby reducing influence of compression and tension forces being applied to the walls of the lumens 320 ₁-320 _(M), not the core fibers 137 ₁-137 _(M) themselves.

As further shown in FIGS. 3A-3B, the core fibers 137 ₁-137 ₄ may include central core fiber 137 ₁ residing within a first lumen 320 ₁ formed along the first neutral axis 230 and a plurality of core fibers 137 ₂-137 ₄ residing within lumens 320 ₂-320 ₄ each formed within different areas of the cladding 300 radiating from the first neutral axis 230. In general, the core fibers 137 ₂-137 ₄, exclusive of the central core fiber 137 ₁, may be positioned at different areas within a cross-sectional area 305 of the cladding 300 to provide sufficient separation to enable three-dimensional sensing of the multi-core optical fiber 135 based on changes in wavelength of incident light propagating through the core fibers 137 ₂-137 ₄ and reflected back to the console for analysis.

For example, where the cladding 300 features a circular cross-sectional area 305 as shown in FIG. 3B, the core fibers 137 ₂-137 ₄ may be positioned substantially equidistant from each other as measured along a perimeter of the cladding 300, such as at “top” (12 o'clock), “bottom-left” (8 o'clock) and “bottom-right” (4 o'clock) locations as shown. Hence, in general terms, the core fibers 137 ₂-137 ₄ may be positioned within different segments of the cross-sectional area 305. Where the cross-sectional area 305 of the cladding 300 has a distal tip 330 and features a polygon cross-sectional shape (e.g., triangular, square, rectangular, pentagon, hexagon, octagon, etc.), the central core fiber 137 ₁ may be located at or near a center of the polygon shape, while the remaining core fibers 137 ₂-137 _(M) may be located proximate to angles between intersecting sides of the polygon shape.

Referring still to FIGS. 3A-3B, operating as the conductive medium for the stylet 120, the braided tubing 310 provides mechanical integrity to the multi-core optical fiber 135 and operates as a conductive pathway for electrical signals. For example, the braided tubing 310 may be exposed to a distal tip of the stylet 120. The cladding 300 and the braided tubing 310, which is positioned concentrically surrounding a circumference of the cladding 300, are contained within the same insulating layer 350. The insulating layer 350 may be a sheath or conduit made of protective, insulating (e.g., non-conductive) material that encapsulates both for the cladding 300 and the braided tubing 310, as shown.

Referring to FIG. 4A, a second exemplary embodiment of the stylet of FIG. 1B is shown in accordance with some embodiments. Referring now to FIG. 4A, a second exemplary embodiment of the stylet 120 of FIG. 1B supporting both an optical and electrical signaling is shown. Herein, the stylet 120 features the multi-core optical fiber 135 described above and shown in FIG. 3A, which includes the cladding 300 and the first plurality of core fibers 137 ₁-137 _(M) (M≥3; M=4 for embodiment) residing within the corresponding plurality of lumens 320 ₁-320 _(M). For this embodiment of the disclosure, the multi-core optical fiber 135 includes the central core fiber 137 ₁ residing within the first lumen 320 ₁ formed along the first neutral axis 230 and the second plurality of core fibers 137 ₂-137 ₄ residing within corresponding lumens 320 ₂-320 ₄ positioned in different segments within the cross-sectional area 305 of the cladding 300. Herein, the multi-core optical fiber 135 is encapsulated within a conductive tubing 400. The conductive tubing 400 may feature a “hollow” conductive cylindrical member concentrically encapsulating the multi-core optical fiber 135.

Referring to FIGS. 4A-4B, operating as a conductive medium for the stylet 120 in the transfer of electrical signals (e.g., ECG signals) to the console, the conductive tubing 400 may be exposed up to a tip 410 of the stylet 120. For this embodiment of the disclosure, a conductive epoxy 420 (e.g., metal-based epoxy such as a silver epoxy) may be affixed to the tip 410 and similarly joined with a termination/connection point created at a proximal end 430 of the stylet 120. The cladding 300 and the conductive tubing 400, which is positioned concentrically surrounding a circumference of the cladding 300, are contained within the same insulating layer 440. The insulating layer 440 may be a protective conduit encapsulating both for the cladding 300 and the conductive tubing 400, as shown.

Referring to FIG. 5A, an elevation view of a first illustrative embodiment of a catheter including integrated tubing, a diametrically disposed septum, and micro-lumens formed within the tubing and septum is shown in accordance with some embodiments. Herein, the catheter 130 includes integrated tubing, the diametrically disposed septum 510, and the plurality of micro-lumens 530 ₁-530 ₄ which, for this embodiment, are fabricated to reside within the wall 500 of the integrated tubing of the catheter 130 and within the septum 510. In particular, the septum 510 separates a single lumen, formed by the inner surface 505 of the wall 500 of the catheter 130, into multiple lumen, namely two lumens 540 and 545 as shown. Herein, the first lumen 540 is formed between a first arc-shaped portion 535 of the inner surface 505 of the wall 500 forming the catheter 130 and a first outer surface 555 of the septum 510 extending longitudinally within the catheter 130. The second lumen 545 is formed between a second arc-shaped portion 565 of the inner surface 505 of the wall 500 forming the catheter 130 and a second outer surfaces 560 of the septum 510.

According to one embodiment of the disclosure, the two lumens 540 and 545 have approximately the same volume. However, the septum 510 need not separate the tubing into two equal lumens. For example, instead of the septum 510 extending vertically (12 o'clock to 6 o'clock) from a front-facing, cross-sectional perspective of the tubing, the septum 510 could extend horizontally (3 o'clock to 9 o'clock), diagonally (1 o'clock to 7 o'clock; 10 o'clock to 4 o'clock) or angularly (2 o'clock to 10 o'clock). In the later configuration, each of the lumens 540 and 545 of the catheter 130 would have a different volume.

With respect to the plurality of micro-lumens 530 ₁-530 ₄, the first micro-lumen 530 ₁ is fabricated within the septum 510 at or near the cross-sectional center 525 of the integrated tubing. For this embodiment, three micro-lumens 530 ₂-530 ₄ are fabricated to reside within the wall 500 of the catheter 130. In particular, a second micro-lumen 530 ₂ is fabricated within the wall 500 of the catheter 130, namely between the inner surface 505 and outer surface 507 of the first arc-shaped portion 535 of the wall 500. Similarly, the third micro-lumen 530 ₃ is also fabricated within the wall 500 of the catheter 130, namely between the inner and outer surfaces 505/507 of the second arc-shaped portion 555 of the wall 500. The fourth micro-lumen 530 ₄ is also fabricated within the inner and outer surfaces 505/507 of the wall 500 that are aligned with the septum 510.

According to one embodiment of the disclosure, as shown in FIG. 5A, the micro-lumens 530 ₂-530 ₄ are positioned in accordance with a “top-left” (10 o'clock), “top-right” (2 o'clock) and “bottom” (6 o'clock) layout from a front-facing, cross-sectional perspective. Of course, the micro-lumens 530 ₂-530 ₄ may be positioned differently, provided that the micro-lumens 530 ₂-530 ₄ are spatially separated along the circumference 520 of the catheter 130 to ensure a more robust collection of reflected light signals from the outer core fibers 570 ₂-570 ₄ when installed. For example, two or more of micro-lumens (e.g., micro-lumens 530 ₂ and 530 ₄) may be positioned at different quadrants along the circumference 520 of the catheter wall 500.

Referring to FIG. 5B, a perspective view of the first illustrative embodiment of the catheter of FIG. 5A including core fibers installed within the micro-lumens is shown in accordance with some embodiments. According to one embodiment of the disclosure, the second plurality of micro-lumens 530 ₂-530 ₄ are sized to retain corresponding outer core fibers 570 ₂-570 ₄, where the diameter of each of the second plurality of micro-lumens 530 ₂-530 ₄ may be sized just larger than the diameters of the outer core fibers 570 ₂-570 ₄. The size differences between a diameter of a single core fiber and a diameter of any of the micro-lumen 530 ₁-530 ₄ may range between 0.001 micrometers (μm) and 1000 μm, for example. As a result, the cross-sectional areas of the outer core fibers 570 ₂-570 ₄ would be less than the cross-sectional areas of the corresponding micro-lumens 530 ₂-530 ₄. A “larger” micro-lumen (e.g., micro-lumen 530 ₂) may better isolate external strain being applied to the outer core fiber 570 ₂ from strain directly applied to the catheter 130 itself. Similarly, the first micro-lumen 530 ₁ may be sized to retain the center core fiber 570 ₁, where the diameter of the first micro-lumen 530 ₁ may be sized just larger than the diameter of the center core fiber 570 ₁.

As an alternative embodiment of the disclosure, one or more of the micro-lumens 530 ₁-530 ₄ may be sized with a diameter that exceeds the diameter of the corresponding one or more core fibers 570 ₁-570 ₄. However, at least one of the micro-lumens 530 ₁-530 ₄ is sized to fixedly retain their corresponding core fiber (e.g., core fiber retained with no spacing between its lateral surface and the interior wall surface of its corresponding micro-lumen). As yet another alternative embodiment of the disclosure, all the micro-lumens 530 ₁-530 ₄ are sized with a diameter to fixedly retain the core fibers 570 ₁-570 ₄.

Referring to FIGS. 6A-6B, flowcharts of methods of operations conducted by the medical instrument monitoring system of FIGS. 1A-1B to achieve optic 3D shape sensing are shown in accordance with some embodiments. Herein, the catheter includes at least one septum spanning across a diameter of the tubing wall and continuing longitudinally to subdivide the tubing wall. The medial portion of the septum is fabricated with a first micro-lumen, where the first micro-lumen is coaxial with the central axis of the catheter tubing. The first micro-lumen is configured to retain a center core fiber. Two or more micro-lumen, other than the first micro-lumen, are positioned at different locations circumferentially spaced along the wall of the catheter tubing. For example, two or more of the second plurality of micro-lumens may be positioned at different quadrants along the circumference of the catheter wall.

Furthermore, each core fiber includes a plurality of sensors spatially distributed along its length between at least the proximal and distal ends of the catheter tubing. This array of sensors is distributed to position sensors at different regions of the core fiber to enable distributed measurements of strain throughout the entire length or a selected portion of the catheter tubing. These distributed measurements may be conveyed through reflected light of different spectral widths (e.g., specific wavelength or specific wavelength ranges) that undergoes certain wavelength shifts based on the type and degree of strain.

According to one embodiment of the disclosure, as shown in FIG. 6A, for each core fiber, broadband incident light is supplied to propagate through a particular core fiber (block 600). Unless discharged, upon the incident light reaching a sensor of a distributed array of sensors measuring strain on a particular core fiber, light of a prescribed spectral width associated with the first sensor is to be reflected back to an optical receiver within a console (blocks 605-610). Herein, the sensor alters characteristics of the reflected light signal to identify the type and degree of strain on the particular core fiber as measured by the first sensor (blocks 615-620). According to one embodiment of the disclosure, the alteration in characteristics of the reflected light signal may signify a change (shift) in the wavelength of the reflected light signal from the wavelength of the incident light signal associated with the prescribed spectral width. The sensor returns the reflected light signal over the core fiber and the remaining spectrum of the incident light continues propagation through the core fiber toward a distal end of the catheter tubing (blocks 625-630). The remaining spectrum of the incident light may encounter other sensors of the distributed array of sensors, where each of these sensors would operate as set forth in blocks 605-630 until the last sensor of the distributed array of sensors returns the reflected light signal associated with its assigned spectral width and the remaining spectrum is discharged as illumination.

Referring now to FIG. 6B, during operation, multiple reflected light signals are returned to the console from each of the plurality of core fibers residing within the corresponding plurality of micro-lumens formed within a catheter, such as the catheter of FIG. 1B. In particular, the optical receiver receives reflected light signals from the distributed arrays of sensors located on the center core fiber and the outer core fibers and translates the reflected light signals into reflection data, namely electrical signals representative of the reflected light signals including wavelength shifts caused by strain (blocks 650-655). The reflection data classification logic is configured to identify which core fibers pertain to which reflection data and segregate reflection data provided from reflected light signals pertaining to a particular measurement region (or similar spectral width) into analysis groups (block 660-665).

Each analysis group of reflection data is provided to shape sensing logic for analytics (block 670). Herein, the shape sensing logic compares wavelength shifts at each outer core fiber with the wavelength shift at the center core fiber positioned along central axis and operating as a neutral axis of bending (block 675). From this analytics, on all analytic groups (e.g., reflected light signals from sensors in all or most of the core fibers), the shape sensing logic may determine the shape the core fibers have taken in three-dimensional space, from which the shape sensing logic can determine the current physical state of the catheter in three-dimension space (blocks 680-685).

Referring now to FIG. 7A, an exemplary embodiment of the medical instrument monitoring system of FIG. 1A during operation and insertion of the catheter into a patient is shown in accordance with some embodiments. Herein, the catheter 195 generally includes integrated tubing with a proximal portion 720 that generally remains exterior to the patient 700 and a distal portion 730 that generally resides within the patient vasculature after placement is complete. The stylet 120 may be advanced through the catheter 195 to a desired position within the patient vasculature such that a distal end (or tip) 735 of the stylet 120 (and hence a distal end of the catheter 195) is proximate the patient's heart, such as in the lower one-third (⅓) portion of the Superior Vena Cava (“SVC”) for example. For this embodiment, various instruments may be placed at the distal end of the stylet 120 and/or the catheter 195 to measure pressure of blood in a certain heart chamber and in the blood vessels, view an interior of blood vessels, or the like.

During advancement through a patient vasculature, the stylet 120 receives broadband incident light 155 from the console 110 via optical fiber(s) 147 within the interconnect 145, where the incident light 155 propagates to the core fibers 137 of the stylet 120. According to one embodiment of the disclosure, the connector 146 of the interconnect 145 terminating the optical fiber(s) 147 may be coupled to the optical-based catheter connector 144, which may be configured to terminate the core fibers 137 deployed within the stylet 120. Such coupling optically connects the core fibers 137 of the stylet 120 with the optical fiber(s) 147 within the interconnect 145. The optical connectivity is needed to propagate the incident light 155 to the core fibers 137 and return the reflected light signals 150 to the optical logic 180 within the console 110 over the interconnect 145. As described below in detail, the physical state of the stylet 120 and the catheter 195 may be ascertained based on analytics of the wavelength shifts of the reflected light signals 150.

Referring to FIG. 7B, a detailed view of the stylet of FIG. 7A in the Superior Vena Cava (SVC) advancing toward the right atrium of the patient is shown in accordance with some embodiments. FIG. 7B illustrates a portion of FIG. 7A providing a detailed perspective of the vasculature proximate to the heart as well as the anatomy of the heart. Specifically, as the stylet 120 approaches the right atrium 746 through the SVC 742, the stylet 120 may either advance into the right atrium 746 or deviate into the Azygos vein 743. The stylet 120 is often used to locate a particular point in the vasculature at which point the catheter may be used to administer a medical procedure or medicament, where this point may be referred to as the “target site” (as shown in FIG. 8 ). Numerous methodologies for detecting deviation of the stylet 120 into the Azygos vein 743 are disclosed below.

In some embodiments, the shape sensing logic 194 is configured to determine the shape the core fibers have taken in 3D space as the stylet 120 advances through a patient's vasculature and may further determine the current physical state of the stylet 120 (and hence the catheter 195) in 3D space for rendering on the display 170. According to one embodiment of the disclosure, the shape sensing logic 194 may generate a rendering of the current physical state of the catheter 195 based on the physical state of the stylet 120 based on heuristics or run-time analytics. For example, the shape sensing logic 196 may be configured in accordance with machine-learning techniques to access a data store (library) with pre-stored data (e.g., images, etc.) pertaining to different regions of the catheter 195 in which the core fibers 137 experienced similar or identical wavelength shifts.

In some embodiments, a subset of the images included in the pre-stored data (or a separate set of images stored in the Azygos detection data 199) may depict particular placements of the stylet 120 as its advancement progresses into the Superior Vena Cava (SVC) and nears the right atrium. Specifically, the subset of the images may include both images in which advancement of the stylet 120 is following a desired or expected path through the SVC and into the right atrium (e.g., to a predetermined target site), and images in which advancement of the stylet 120 deviates from the desired or expected path and enters into the Azygos vein. Further, following generation of the physical state of the stylet 120, such may be compared using heuristics or run-time analytics to the subset of images depicting advancement along desired (expected) and undesired (unexpected) paths in order determine whether the stylet 120 has deviated into the Azygos vein. For example, the analyses performed by the Azygos detection logic 196 may result in a determination indicating whether stylet 120 and/or the catheter 195 have entered the Azygos vein.

Referring to FIG. 8 , a first illustration of a stylet advancing through a patient's vasculature toward the right atrium of the patient's heart is shown in accordance with some embodiments. As seen, the stylet 120 is advancing through the SVC 742 toward a target site 800 within the right atrium 746 but has deviated from a desired path into the Azygos vein 743. In one embodiment, as the stylet 120 advances toward the Azygos vein 743 the reflected light generated by the sensors (reflective gratings) indicates such a curvature. The Azygos detection logic 198 obtains the generated physical state of the stylet 120 from the shape sensing logic 194 and, through heuristics and/or run-analytics determines the generated physical state of the stylet indicates entry into the Azygos vein 743. As referenced above, such a determination may be based on, at least in part, comparison through machine-learning tactics (and, optionally, in combination with image recognition algorithms) to a set of pre-stored images. For instance, a trained machine-learning model may provide an indication that the stylet 120 has entered into the Azygos vein 743 with a particular confidence level. As should be understood, the machine-learning model would previously trained using the pre-stored images of both (i) stylets advancing properly toward the right atrium 746 generation of the physical state of the stylet 120 generation of the physical state of the stylet 120 and (ii) stylets deviating into the Azygos vein 743.

Additionally, or as an alternative, the Azygos detection logic 198 may analyze the reflected light with respect to fluctuations of the stylet 120 during its advancement in order to determine whether the stylet 120 has deviated into the Azygos vein 743. For instance, known or expected rates of fluctuation may be pre-stored as part of the Azygos detection data 199 for various areas of the human vasculature. These known rates of fluctuation may be compared to a current rate of fluctuation of the stylet 120 computed by the Azygos detection logic 198 based on the reflected light, which indicates movement of the stylet 120. The difference in the fluctuations of the stylet 120 between the SVC 742 and the Azygos vein 743 may be a result of one or more several factors including more turbulent blood flow in the SVC 742, a larger diameter of the SVC 742, a difference in pulsatility between the SVC 742 and the Azygos vein 743, and a difference in the volumes of interiors of the SVC 742 and the Azygos vein 743. The amount or rate of fluctuation of the stylet 120 may be a combination of movement by the stylet 120, especially the distal tip, in any direction within the particular portion of the vasculature through which the stylet 120 is currently traveling.

In particular and referring again to FIG. 8 , the SVC 742 is illustrated as having a diameter (D1) 802 and the Azygos vein 743 is illustrated as having a diameter (D2) 804, where the D2 804 of the Azygos vein 743 is less than the D1 802 of the SVC 742. Thus, the larger diameter of the SVC 742 enables the stylet 120 to have a higher rate of fluctuation over a particular stretch of advancement than does the smaller diameter of the Azygos vein 743, i.e., the stylet 120 is more limited in its physical movement upon deviating into the Azygos vein 743.

Additionally, the higher rate of fluctuations may be caused by the contraction of the cardiac muscle of the heart and the actuation of heart valves adjacent to the path of the blood. Specifically, these contractions and actuations interrupt the steady blow flow in the SVC 742, where the steady blood flow is more broadly observed throughout the rest of the venous vasculature. In the regions immediately adjacent to the heart, e.g., the SVC, vessel properties are unable to flatten and filter these disruptions to steady blood flow resulting in an observable movement (fluctuation) within the stylet 120 when present in this region of the vasculature. Thus, the Azygos detection logic 198 may detect deviation into the Azygos vein 198 based on a lower rate of fluctuation that is at least in part caused by the contractions and actuations discussed above, where the rate of fluctuation is indicated in the reflected light.

In yet other embodiments, the direction of blood flow may be utilized as an indicator that the stylet 120 has deviated into the Azygos vein 743. Specifically, as illustrated in FIG. 8 , the direction of blood flow in the SVC 742 is illustrated via the arrow 806 (i.e., in-line with the direction of advancement of the stylet 120) and the direction of blood flow in the Azygos vein 743 is illustrated via the arrow 808 (i.e., against the direction of advancement of the stylet 120). Thus, utilizing data obtained through pulse oximetry and/or flow Doppler, typically in addition to one or more of the embodiments discussed herein, a directional flow detection logic 199 may determine that the stylet 120 has deviated into the Azygos vein 743. The directional flow detection logic 199 may be a sub-logic module of the Azygos detection logic 198. For example, technology implementing pulse oximetry and/or an optical-based Doppler (e.g., Doppler ultrasound) may integrated into the stylet 120 and provide the Azygos detection logic 198 with readings regarding blood oxygen levels and blood flow velocity, which aid the Azygos detection logic 198 in determining whether the distal tip of the body of implementation has deviated into the Azygos vein.

In some embodiments, the stylet 120 and/or the catheter 195 may be operable to perform intravascular ECG monitoring in addition to the fiber optic shape sensing functionality discussed previously. As indicated above, the console 110 may include the electrical signaling logic 181, which is positioned to receive one or more electrical signals from the stylet 120 and/or catheter 195 when configured to obtain electrical signals, e.g., at a distal tip. Further, the stylet 120 is operable to support both optical connectivity as well as electrical connectivity. The electrical signaling logic 181 receives the electrical signals (e.g., ECG signals) from the stylet 120 via the conductive medium 144. The electrical signals may be processed by electrical signal analytic logic 196, executed by the processor 160, to determine ECG waveforms for display.

Referring to FIG. 9 , a second illustration of a stylet advancing through a patient's vasculature toward the right atrium of the patient's heart is shown in accordance with some embodiments. As is known and illustrated in FIG. 9 , the SA node 900 generates electrical impulses that control the sinus rhythm of the heart. Such as impulses are detectable by, for example, an electrode coupled to a distal tip of the stylet 120. As the stylet 120 deviates into the Azygos vein 743, the detected P-wave of the intravascular ECG decreases slightly in amplitude even as the stylet 120 is advanced toward the sinoatrial (SA) node 900.

Referring to now FIGS. 10A-10C, illustrations depicting an electrode configuration that provides for acquisition of endovascular ECG data are shown in accordance some embodiments. With specific reference to FIG. 10A, the illustration depicts a single lead configuration with a reference electrode 1006 that is, for example, attached to the patient's skin over the right arm and with a secondary electrode 1008 coupled to the stylet 120 or catheter 195. It should be noted that the reference electrode 1006 is attached to the skin over the right arm for illustration purposes only with other configurations being possible depending on the type of ECG required. Such a configuration enables ECG data to be obtained from the SVC 1002 and inferior vena cava 1004.

With reference to FIG. 10B, the illustration depicts a modified 3-lead configuration, with monitoring and guiding capabilities utilizing four electrodes. In such a configuration, three of the electrodes correspond to standard ECG electrodes: right arm (RA) 1010, left arm (LA) 1012, and left leg (LL) 1014 (not shown to proportion), wherein the left leg electrode 1014 is used as reference. The fourth electrode 1016 is attached through to the stylet 120 or catheter 195. In this configuration, the console 110 and the electrical signal analytic logic 196 may perform two functions simultaneously or concurrently (at least partially overlapping in time): the three standard electrodes (1010, 1012, 1014) perform a monitoring function of the heart, while the fourth electrode 1016 allows for recording the ECG at the tip of the stylet 120 or catheter 195. FIG. 10C provides an illustration depicting a telemetry configuration with a single grounded lead 1018 in addition to the configuration as discussed in FIG. 10A utilizing electrodes 1006 and 1008. This configuration can be used to transmit ECGs remotely through a telemetry system configuration.

Referring to now FIG. 11 , an illustration of an exemplary peripherally inserted central catheter is shown in accordance with some embodiments. The device 1100 comprises or is configured as a central venous catheter (CVC), such as, a peripherally inserted central catheter (PICC or PICC line), with a detector 1102 positioned at or near a distal end 1104 of device 1100. Additionally, the device 1100 is configured with a multi-core optical fiber, which receives broadband incident light and reflects optical signals (light signals) to a console as discussed above. In some embodiments, the multi-core optical fiber may be integrated into an interior of the device 1100 (e.g., when the device 1100 is a guidewire or a stylet). In other embodiments, the multi-core optical fiber may be integrated into a wall of device 1100 (e.g., when the device 1100 is a catheter).

The device 1100 itself comprises an elongated body 1106 that is made of a material that may permit delivery of device 1100 into a luminal organ (or an access route through another bodily part) of a patient and subsequent withdrawal from the patient without damaging the patient. For example, elongated body 1106 may comprise silicone or one or more other polycarbonates so to prevent device 1100 from “sticking” to the vasculature of the patient during or after insertion. In various device 1100 embodiments, at least one lumen 1108 is defined within elongated body 1106, and may define multiple lumens 1108. In other embodiments (such as wire embodiments, for example), device 1100 would not have a lumen therethrough.

The detector 1102 comprises a pair of detection electrodes 1114, 1116 that are positioned in between a pair of excitation electrodes 1110, 1112. The detector 1102 is configured to generate an electric field and also to obtain multiple conductance measurements within the electric field as the detector 1102 is advanced through a patient's vasculature, wherein each of the multiple conductance measurements is indicative of a location of the detector 1102 within the patient's vasculature when the detector 1102 is positioned therein.

Referring now to FIG. 12 , an illustration of a system utilizing a second embodiment of a peripherally inserted central in conjunction with two electrode pads is shown in accordance with some embodiments. In the embodiment shown in FIG. 12 , an electric field is generated by electrodes that are coupled to or positioned on the pads 1202, 1204. In such an embodiment, changes in conductance can be obtained using detector 1206, which includes detection electrodes 1208, 1210 that are similar to the detection electrodes 1114, 1116, for example) as the detector 1206 moves with stylet 1205 through the patient's vasculature.

In such an embodiment, upon activation of distal excitation electrode 110 and proximal excitation electrode 112, the electric field detectable by detection electrodes 1208, 1210 of the detector 1206. As stylet 1205 is advanced through the patient's vasculature, from vessels of smaller diameter/cross-sectional area to larger vessels and ultimately to the heart, stepwise changes (increases) in conductance can be identified, and the anticipated pulsatile nature of voltage change due to the pumping of the heart can also be identified, indicating delivery of a distal end of stylet 1205 to the right atrium.

Specifically, in embodiments in which the pads 1202, 1204 may themselves serve as the poles or excitation electrodes may be positioned upon the pads 1202, 1204, the stylet 1205 need not include excitation electrodes (such as excitation electrodes 1110, 1112 of FIG. 11 ) positioned thereon as the two poles are provided using pads 1202, 1204 as shown in FIG. 12 . In some embodiments, one or more wires (not shown) may be connected to the pads 1202, 1204 to transmit a current from an ECG/EKG device (and/or the console 110), so to generate an electric field detectable by a stylet 1205.

As shown in FIG. 12 , the pads 1202, 1034 are each positioned upon the patient's torso. While other locations may be used, the illustrated embodiment includes pad placement whereby the pad 1202 is positioned adjacent to a vein that the stylet 1205 will pass through on the way to the right atrium, and the pad 1204 is positioned adjacent to the right ventricle or the right atrium of the heart (or generally positioned away from the pad 1202, such as on an opposing arm of a patient, at or near the patient's neck, elsewhere on the torso, etc.).

In an embodiment in which the two pads 1202, 1204 are poles and generate the electric field, when a detection portion of stylet 1205 is outside the field, conductance is generally high and voltage is very low, and when the detection portion of stylet 1205 moves back into the field, conductance significantly drops, while voltage increases.

While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein. 

What is claimed is:
 1. A medical device system for detecting malposition of a medical device within a vessel of a patient, the system comprising: the medical device comprising a multi-core optical fiber having a plurality of core fibers, each of the plurality of core fibers including a plurality of sensors distributed along a longitudinal length of a corresponding core fiber and each sensor of the plurality of sensors being configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber; and a console including one or more processors and a non-transitory computer-readable medium having stored thereon logic, when executed by the one or more processors, causes operations including: providing a broadband incident light signal to the multi-core optical fiber, receiving reflected light signals of different spectral widths of the broadband incident light reflected by each of the plurality of sensors, processing the reflected light signals associated with the plurality of core fibers, and determining whether the medical device has entered the vessel of the patient based on the reflected light signals.
 2. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on a shape of the medical device indicated by the reflected light signals.
 3. The system of claim 2, wherein the shape of the medical device indicated by the reflected light signals is utilized as input to a machine-learning configured to process the input and provide a result indicating a confidence level as to whether the shape of the medical device indicates entry into the vessel of the patient.
 4. The system of claim 2, wherein determining whether the medical device has entered the vessel is based a result of heuristics performed on the shape of the medical device indicated by the reflected light signals.
 5. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on an amount of fluctuation of the medical device indicated by the reflected light signals.
 6. The system of claim 5, wherein the amount of fluctuation of the medical device is an amount of fluctuation at a distal tip of the medical device.
 7. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on a shape of the medical device indicated by the reflected light signals and electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient.
 8. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on a shape of the medical device indicated by the reflected light signals and impedance sensing of advancement of the medical device through a vasculature of the patient.
 9. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on (i) a shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, and (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient.
 10. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on a shape of the medical device indicated by the reflected light signals and detection of a direction of blood flow within a portion of a vasculature of the patient in which the medical device is currently disposed.
 11. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on a shape of the medical device indicated by the reflected light signals and one or more of (i) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (ii) impedance sensing of the advancement of the medical device through the vasculature of the patient, or (iii) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.
 12. The system of claim 1, wherein determining whether the medical device has entered the vessel is based on (i) a shape of the medical device indicated by the reflected light signals, (ii) electrocardiogram (ECG) monitoring of advancement of the medical device through a vasculature of the patient, (iii) impedance sensing of the advancement of the medical device through the vasculature of the patient, and (iv) detection of a direction of blood flow within a portion of the vasculature of the patient in which the medical device is currently disposed.
 13. The system of claim 1, wherein at least two of the plurality of core fibers experience different types of strain in response to changes in an orientation of the multi-core optical fiber.
 14. The system of claim 1, wherein the vessel is the Azygos vein.
 15. The system of claim 1, wherein the medical device is a stylet removably inserted into a lumen of a catheter assembly for placement of a distal tip of the catheter assembly in a superior vena cava of the patient.
 16. The system of claim 13, wherein the different types of strain include compression and tension.
 17. The system of claim 1, wherein each of the plurality of sensors is a reflective grating, wherein each reflective grating alters its reflected light signal by applying a wavelength shift dependent on a strain experienced by the reflective grating. 